Bright Dot Defects; Dark Dot Defects; Proximity Of Pixel Defects; Pixel Defect Tolerances - Philips BDL4771V User Manual

User Manual BDL4771V
6.3.

BRIGHT DOT DEFECTS

Bright dot defects appear as pixels or sub-pixels that are always lit or "on". These are the examples of bright dot defects:
One lit red, green or blue sub-pixel
6.4.

DARK DOT DEFECTS

Black dot defects appear as pixels or sub-pixels that are always dark or "off". These are the examples of black dot
defects:
One dark dot
6.5.

PROXIMITY OF PIXEL DEFECTS

Because pixel and sub-pixels defects of the same type that are nearby one another may be more noticeable, Philips also
specifies tolerances for the proximity of pixel defects. In the table below you can find specifications about:
• Allowed amount of adjacent dark dots = (adjacent dark dots =1 pair of dark dots)
• Minimum distance between dark dots
• Total no. of all defective dots
6.6.

PIXEL DEFECT TOLERANCES

In order to qualify for repair due to pixel defects during the warranty period, a PDP/TFT panel in a Philips LCD display
must have pixel or sub-pixel defects exceeding the tolerances listed in the following table.
BRIGHT DOT EFFECT
MODEL
1 lit sub pixel
BLACK DOT EFFECT
1 dark sub pixel
TOTAL DOT DEFECTS OF ALL TYPES
Note: * 1 or 2 adjacent sub pixel defects = 1 dot defect
6.7.

MURA

Dark spots or patches may occasionally appear on some liquid crystal display (LCD) panels. This is known within the
industry as Mura, which is a Japanese term for "unevenness." It is used to describe an irregular pattern or area in which
uneven screen uniformity appears under certain conditions. Mura is a result of the deterioration of the liquid crystal
alignment layer and is most commonly caused by long-term operation under high ambient temperatures. It is an industry-
wide phenomenon and Mura is not repairable. It is also not covered by our warranty terms.
Two adjacent lit sub-pixels:
- Red + Blue = Purple
- Red + Green = Yellow
- Green + Blue = Cyan (Light Blue)
Two adjacent dark dots = 1 pair of
dark dots
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Three adjacent lit sub-pixels (one
white dot)
Two dark dots, specifications define
the minimum distance between dark
dots
ACCEPTABLE LEVEL
BDL4771V
10
ACCEPTABLE LEVEL
8
9